Validation of relative value scale for congenital heart operations

To determine the validity of the newly assigned work relative value unit (RVU) scale for surgical procedures for congenital heart disease, we measured its relationship to length of hospital stay, total hospital charges, and mortality.

We identified cases by the presence of ICD-9-CM codes in nine statewide, administrative hospital discharge abstract databases for 1992. Computer algorithms were generated to assign RVUs to individual cases. Spearman correlation coefficients between work and practice expense RVUs and median length of hospital stay, total hospital charges, and in-hospital mortality were determined, as well as parameter estimates from linear and logistic regression.

Using data from 5,192 cases involving 34 surgical procedures for congenital heart disease, higher work RVUs were associated with longer lengths of hospital stay (rs = 0.72, p < 0.0001), higher total hospital charges (rs = 0.81, p < 0.0001), and higher in-hospital mortality (rs = 0.45, p = 0.01). A 5-point increase in the relative value scale was associated with an increase in the length of stay by a multiplicative factor of 1.3 (p < 0.0001); total hospital charges by 1.5 (p < 0.0001); and the odds of in-hospital death by 1.9 (p < 0.0001). Findings were similar for practice expense RVUs, as work and practice expense RVUs were highly correlated (rs = 0.93, p < 0.0001).

The group of work RVUs for surgical procedures for congenital heart defects are reasonable relative measures, on average, of physician work for these procedures, thus supporting the use of this scale to determine physician reimbursement. Practice expense RVUs may not be an independent measure for these procedures.